D3396: Volatile emissions by male and female red sunflower seed weevil, Smicronyx fulvus (Le Conte) (Coleoptera: Curculionidae) and antennal discrimination by conspecifics from the laboratory and field

The red sunflower seed weevil, Smicronyx fulvus (Le Conte) (Coleoptera: Cucurlionidae) is a pest of sunflowers, and it is considered the most serious seed-feeding pest of sunflowers in recent years in the northern Great Plains. This weevil is univoltine, and typically emerges from the soil in early summer when adults move to blooming sunflowers, and feed on the pollen. It is known that plant volatiles are important in its chemical ecology, but thus far no sex or aggregation pheromones have been identified for this species. Thus, for the first time, we have collected volatile emissions from 1 individual, a group of 2, 4, 8 of males only, females only, or mixed sex groupings of S. fulvus using solid phase microextraction (SPME) coupled with gas chromatography and mass spectrometry (GC/MS). We collected for 1, 2, 4, 8 hours during the day, or 24 hours to span multiple potential calling and activity periods by weevils. In addition, we also collected volatile emissions from conspecifics and tested male and female antennal discrimination from diapausing individuals and individuals collected from the field using a gas chromatograph coupled with an electroantennographic detector (GC/EAD). We found several characteristic volatile profiles produced by each sex, and consistent response to a subset of peaks in each profile, suggesting future targets for pheromone identification. Overall, our research adds to the information available about the chemical ecology of S. fulvus, and may eventually help with developing behaviorally-based management programs.